For Sèvres sculptures:
- The royal cypher (two opposing “L”s) is never engraved on the bottom of 18th-century sculptures.
- The sculptor’s name or signature is never present on 18th-century models, not appearing until the late 19th century (excepting the bust of Napoleon by Chaudet).
For decorated pieces of porcelain:
- Works representing Napoleon and his family are well recorded in the archives and their existence can be verified. Painters signing Desprez, Bertren or Poitevin never worked for the Manufacture.
- Château marks (Tuileries, Fontainebleau, etc.) are only to be found on porcelain pieces bearing simple cyphers (lent between palaces for large receptions, they needed a château mark for their correct return). These pieces are never adorned with draperies or cherubs (added outside the Manufacture when sold in great quantities by the Administration des Domaines after 1870). Château marks are not found on decorative objects that were never lent or borrowed.
- The oval, chromium-green manufacture mark beneath the glaze, formed by the letters “SV” with the last two numbers of the calendar year, was only used from 1848 onwards.
- Starting circa 1860, the Sèvres Manufactory mark is crossed out or scratched on discarded (defective) porcelain pieces. If such pieces are decorated, it is highly likely that these motifs are sur-décors applied outside the Manufacture.
It should be noted that, in accordance with Decree no. 90-404 of 16 May 1990, only state-certified establishments are authorized to provide identifications and expert appraisals.